Bleeder and equalizer for blast furnaces



1952 KI. G. LE VISEUR ETAL BLEEDER AND EQUALIZER FOR BLAST FURNACESFiled Sept. 5, 1947 IN V EN TORS.

KURT. G. LE VISEURF/ YLEONARD LARSON.

ATT RNEYS.

Patented Feb. 12, 1952 BLEEDEB AND EQUALIZED FOR BLAST FURNACES Kurt 'G.Le Viseur, Youngstown, and Leonard Larson, Shaker Heights, Ohio,assignors to Bepublic Steel Corporation, Cleveland, Ohio, a corporationof New Jersey Application September 8, 1947, Serial No. 771,870

Claims.

1 This invention relates generally to the art of blast furnace construction' and operation and is particularly concerned with apparatus bywhich clean gases may be used to equalize the pressure on opposite sidesof the charging bell and may also be vented to the atmosphere instead ofdirty gas whenever slips or rolls of the furnace occur which are ofminor or moderate intensity.

Modern blast furnaces are provided with bleeders above the top of thefurnace through which gases may escape in case of slips or rolls of thefurnace. Such bleeders are located in upward extensionsof the downcomersand permit the escape of dirty gases from the top of the furnace.Heretofore these bleeder valves have been set to openunder low pressuresto take care of minor slips or rolls. In conventional furnaces, intendedto operate on pressures higher than conventional pressures which are onthe order of two to three pounds per square inch, it has been proposedto remove dirty gases from the gas above the stock line and admit theminto the space in the charging hopper between the two charging bells toincrease the pressure on the outer or upper side of the lower or bigbell to an amount approximately equivalent to the pressure within thefurnace to facilitate lowering of the big bell during charging. In thisconnection it has. been suggested that the gas in the charging hopperbetween the bells should be vented to the.

atmosphere through a short pipe at the top of the furnace controlled bya valve.

There are many disadvantages to use of the foregoing proposals. Wheredelivery gas is vented to the atmosphere either from the hopper chamberor from the furnace by reason of slips "to the or rolls, much dirt isdischarged and constitutes a nuisance to adjacent buildings andresidences. Also, the solids in these gases are valuable and constitutea loss to the extent that they are carried out of the furnace.

Th present invention is capable of use with furnaces operating atconventional pressures but is particularly important for use withfurnaces operating at higher than conventional pressures. This inventiononly vents clean gas, that is, gas from the washer, to the atmosphere,from the hopper chamber or as a result of slips and rolls ranging up toa predetermined magnitude above that experienced in ordinary practice.

Among the numerous advantages of thus venting only clean gas is the factbleeder valve erosion, which is especially serious in furnaces operatingat high top pressures, is substantially reduced. v

Our present invention further enables, the automatic equalization ofpressures between the double bell chamber and the atmosphere and betweensaid chamber and the furnace. Thus chambe is being charged. the chamberis open when tge small bell is dumping and the bell tmosphere, and whenthe-large bell is being dumped to charge the furnace, the bell chambercommunicates with a source of gas under pressure and is closed to theatmosphere so that the large bell may be opened easily although thefurnace is being operated at relatively high internal gas pressures.

Briefly described, the present invention includes the usual blastfurnace, dust catcher and washer connected together for the passage of'gase; from the furnace through the dust catcher and into the washer,means to conduct clean gas from the washer to the top of the furnacewhere it may be discharged into the hopper chamber, and a bleeder valvein the clean gas line which is set to open at a pressure considerablylower than the pressure at which the regular bleeder valves are set.

A better understanding ofthis invention and the reasons for itsadvantages will be gained by those skilled in the art upon considerationof the following detailed description and the drawings accompanying andforming a part of this specification, in which,

Figure 1- is a diagrammatic sketch of a blast furnace assembly embodyingthe present invention, and

Figure 2 is an enlarged diagrammatic view of the upper part of thefurnace of Fig. 1 including a double bell charging assembly.

In Fig. 1, the system includes a blast furnace i0 which is provided witha double bell charging assembly ll, top gas uptake conduits l2, ableeder valve l3 in one of the uptake conduits, a downcomer i4communicating with said conduits, a dust catcher l6 and a gas washer I.Double bell assembly H includes a small upper hell I l and a large lowerbell it which are fitted to a charging hopper I! which with the twobells Bell chamber is provided with a bleeder pipe 26 equipped with avalve 26.

Bleeder valves I3 and 22 are of the type which open against gas pressurewithin the bleeder pipes, as by downward movement of the long lever arms21 against the counter-weights 26 on the short lever arms. Means areprovided for opening these bleeder valves at different selected gaspressures within the bleeder pipes. This means includes the system ofpiping, valves and cylinders, shown in Fig. 1. A pipe line 29 leads fromone uptake l2 and is divided into two branches. 3| which operates avalve 32 to control the flow of fluid from a supply 33 to a cylinder 34provided with a piston 35 attached by cable 36 to the lever'arm 21 ofbleeder valve 22. The other branch, 37, leads to a similar diaphragm31a, which operates a valve 38 to control the flow of fluid underpressure from source 39 to cylinder 40 in which piston 4| is slidablymounted. Piston 4| is connected by cable 42 to the long lever arm 21 ofbleeder valve I3. The controls for valve 22 are so adjusted that whenthe gas pressure in pipe line 29 exceeds a certain amount, for example,13 pounds per square inch gauge, diaphragm 3| will actuate valve 32 andadmit fluid under pressure from source 33 to cylinder 34 above piston35, thereby forcing the piston downwardly and opening valve 22. Suddenmoderate increases in gas pressure in the furnace caused by slips orrolls may be relieved in this way and the gas which is allowed to escapethrough valve 22 is clean, coming as it does from the washer and henceis not a public nuisance. When more extensive slips or rolls occur andthe resulting pressure considerably exceeds that required to actuatediaphragm 3|, for example, amounts to 18 pounds per square inch gaugewhich is sufficient to actuate diaphragm 3|a, valve I3 is opened by theadmission of fluid under pressure into cylinder 40 and dirty gas isvented through valve l3 provided for such emergency circumstances. Inthis manner only clean gas is vented during the moderate slips and rollsof the furnace and is supplemented by dirty gas only when slips or rollsof more than ordinary intensity occur.

Fig. 2 shows apparatus for automatically actuating the gas control valvein gas lines 23 and 25 in predetermined sequence with the operation ofthe bells of the charging apparatus. In this view the stock rod cable 43leads from the weight 44 attached thereto inside the furnace verticallyup and over a pulley 45 and then downward to a move ent of cable 46ineither direction.

By reason of the connection of the valve actuating cable 46 with thestock rod cable 43, the opening and closing of valves 24 and 26 issynchronized with movements of the stock rod. The

movements of the stock rod cable are synchronized with movements of thelarge and small charging bells'by means of interconnecting controlswhich are conventional and form no part of the present invention.

The operation of this interconnected charging One branch 30 leads to adiaphragm apparatus is substantially as follows, starting with a furnacein operation with gas pressure above the stock line in the furnace of,for example, 5 pounds p. s. 1. gauge, the valve 24 closed and valve 26open and bells l1 and I8 closed, and the stock rod weight 44 being downat the stock line in the furnace. A quantity of furnace charge isbrought into the rotating hopper whose bottom is closed by small bellll. The small hell I! is lowered and the charge is discharged intochamber 20 onto large bell I8. Another quantity of charge is broughtinto the rotating hopper, the hopper is rotated and the charge is dumpedinto the chamber adjacent to the first charge.

This procedure is continued until the desired amount of chargingmaterial has been accumulated on large bell l8. Thereupon the small bellI1 is closed, the stock rod cable 43 is actuated to pull weight 44 intothe dome of the furnace and simultaneously cable 46 closes valve 26 andopens valve 24. Clean gas from pipe 2| enters chamber 20 and brings thegas pressure in that chamber up approximately to the pressure existingwithin the furnace. Thereupon, large bell I3 is lowered and the chargethereon is delivered into the stack of the furnace. Then large bell i8is returned to closed position. Stock rod cable 43 is slacked off withresultant lowering of the stock rod weight 44 into the furnace andopening of valve 26 and closing of valve 24. The gas under pressure inchamber. 20 bleeds out through pipe 25 to the atmosphere. Then the abovedescribed operation may be repeated.

It will be noted that a valve 60 is shown in conduit 5| which conductsgases away from the top of the washer l6. This valve 50 serves tocontrol the-gas pressure existing in the top part of the furnace, in thegas conduits and in the dust catcher and washer. By suitably adjustingthe position of the valve, gas pressures in these parts may be regulatedso that pressures higher than conventional pressures may be used, forexample, pressures of 5 pounds or more p. s. i. gauge may thus bemaintained in the furnace dust catcher and washer.

Although we have shown and described only one embodiment of our presentinvention, we contemplate others of substantially the same effect andequivalent construction, as will be understood by those skilled in theart. We have in mind,-for instance, operating valves 24 and 26independently of the stock rod in installations where such independenceis desirable. In such.

case instead of cables 43 and 46 being connected as shown in Fig. 2,each would be free and clear of the other.

Having thus described the invention so that A others skilled in the artmay be able to understand and practice the same, we state that what wedesire to secure by Letters Patent is defined in what is claimed.

What is claimed is:

l. The method of operating a blast furnace having a bell chamber whichcomprises the steps of removing from the furnace top gases carryingentrained solids and having the pressures existing in the furnace aboutthe stock line, removing solids from substantially all of said gases,separating the thus cleaned gas into a constantly flowing stream and astream flowing intermittently to said bell chamber, maintaining thepressures of the gases while being cleaned and in the streams of cleanedgases at approximately the pressures existing above the furnace stockline, and releasing gases from the asaaeoo intermittently flowing streamto the atmosphere when the'pressure above-the furnace stock line and inlast mentioned stream reaches a predetermined pressure above the normalfurnace stocl: linepressure.

2. The method of operating a blast furnace having a bell chamber whichcomprises the steps of removing from the furnace top gases carryingentrained solids and having the pressures existing inthe'furnace abovethe stock line, removing solids from substantially all of said gases,separating the thus cleaned gas into two streams, maintaining thepressures of the gases while being cleaned and in the streams of cleanedgases at approximately the pressures existing above the furnace stockline, and periodically releasing gases from one of said streams into thebell chamber of the furnace and from the other stream intotheatmosphere.

3. Themethod of operating a blast furnace having a bell chamber whichcomprises the steps of removing from the furnace top gases carryingentrained solids and having the pressures existing in the furnace abovethe stock line, removing solids from substantially all .of said gases,separating the -thus cleaned gas into two streams, maintaining thepressures of the gases while being cleaned and in the streams of cleanedgases at approximately the pressures existing above the furnace stockline, periodically releasing gases from one of said streams into thebell chamber of the furnace during charging of solids into the furnaceand to the atmosphere from same stream when the pressure above thefurnace stock line and in said stream reaches a predetermined pressureabove the normal furnace stock line pressure.

4. In apparatus of the class described, a blast furnace having a bellchamber, a gas cleaner and -a conduit from said cleaner to a gas main, aconduit connecting the top of the furnace with the cleaner to conducttop furnace gases to said cleaner, a bleeder to permit escape of topgases from the second conduit when such gases attain a predeterminedhigh pressure above their normal pressures, a pipe communicating at oneend with said cleaner and having a main outlet to the atmosphere and abranch outlet having a control valve to the bell chamber, a valve forsaid main outlet, and means for opening said main outlet mined pressureof top furnace gases which is below said high pressure and above thenormal top gas pressure. 1

5. In apparatus of the class described, a blast furnace having a bellchamber, a gas cleaner, a conduit from said cleaner to a gas main, aconduit connecting the top, of the furnace with the cleaner to conducttop furnace gases to said cleaner, a bleeder to permit escape of topgases from the furnace when such gases attain a predetermined highpressure above their normal pressures, a pipe communicating at one endwith said cleaner and having a main outlet to the atmosphere and abranch outlet having a control valve to the bell chamber, a valve forsaid main outlet, a valve for said bleeder, and means responsive to saidpredetermined high pressure of top furnace gases to open said bleedervalve and 1 means responsive to a predetermined gas pressure below saidhigh pressure and above normal top gas pressure to open said main outletvalve.

KURT G. LE VISEUR. LEONARD LARSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 721,418 Berg Feb. 24, 1903759,991 Hamfeldt May 17, 1904 1,727,100 Edwards Sept. 3. 1929 1,856,897Whitcomb May 3, 1932 1,881,272 Grilli Oct; 4, 1932 2,200,488 Clemmitt eta1. May 14, 1940 2,215,872 Fox et a1. Sept. 24, 1940 2,408,945 Mohr,Jr., et a1. Oct. 8, 1946 2,411,487 Whitcomb Nov. 19, 1946 2,516,190Daugherty July 25, 1950 OTHER REFERENCES American Institute of Miningand Metallurgical Engineers, Transactions, Iron and Steel Division,

' vol. 67 (1922), pages-609 and 615.

J. H. Slater: Operation of the Iron Blast Furnace at High Pressure,Yearbook of the American Iron and Steel Institute for 1947, May 21,1947, pages to 127.

